a. Field of the Invention
The present invention concerns an FM receiver, and more particularly it relates to a tuning indicating system and a muting system in an FM receiver.
B. Description of the Prior Art
The tuning indicating system and the muting system of a conventional FM receiver, in general, are arranged to be operative so that a signal is derived from the intermediate frequency (IF) amplifying circuit of the FM receiver, and the signal thus derived is rectified by a rectifier, and the output of this rectifier is used to drive the switching element of the tuning indicating system and the muting system. However, these known tuning indicating system and muting system tend to induce such adverse effects in the IF amplifying circuit as an abnormal oscillation phenomenon of the IF amplifying circuit, or a beat phenomenon occurring between the harmonics which develops during the rectification and the IF signal. In addition thereto, said known systems tend to complicate the IF amplifying circuit arrangement. Furthermore, these known systems are easily accompanied by such problem that the tuning indicating characteristic and the muting characteristic are affected by the frequency characteristics of both the IF amplifying circuit and the radio frequency amplifying circuit of the FM receiver.